CN102436196A - Universal electro-hydraulic position servo driver - Google Patents

Abstract

The invention relates to a universal electro-hydraulic position servo driver. The current electro-hydraulic servo system driver mainly adopts a distributed structure. The SSI conversion module is externally connected with an SSI displacement sensor and used as a driver for preprocessing an input signal, and the ARM7 core is the core of the driver; the operation panel is a visual interactive operation interface and mainly comprises a liquid crystal display, a keyboard input and an LED indicator light; the serial port level conversion module provides an external control interface for the driver, and the computer can realize real-time data communication and accurate system control on the servo driver through the serial port level conversion module; the DA conversion and amplification module adopts a DA module provided by ARM7 and provides a control electric signal for the servo valve or the proportional valve; the power supply module is used for supplying power to each module of the driver. The invention has the advantages of simplicity, higher integration degree, convenient operation and lower cost, and is favorable for large-scale popularization and use.

Description

Universal electro-hydraulic position servo driver

technical field

The invention relates to an integrated driver applied to an electro-hydraulic position servo system, in particular to a general-purpose electro-hydraulic servo driver with functions of digital display, panel control and external control.

Background technique

At the end of the 21st century, the electro-hydraulic servo system developed rapidly and played an increasingly important role in the field of industrial control. The electro-hydraulic servo system is a feedback control system that combines electrical devices and hydraulic actuators. The most common types are electro-hydraulic position servo system, electro-hydraulic speed control system and electro-hydraulic force control system. The electro-hydraulic servo system takes the output of the actuator as the control quantity, mainly to solve the following problem of the control quantity, and realize the timely tracking of the control quantity to the given quantity under the premise of ensuring sufficient accuracy, so the electro-hydraulic servo system is also called the follow-up system. Commonly used hydraulic actuators include hydraulic cylinders and hydraulic motors.

The current electro-hydraulic servo system driver mainly adopts a distributed structure. The specific implementation methods include the industrial computer mode integrating data acquisition and processing boards and the single-chip microcomputer mode integrating high-speed and high-precision AD chips. The shortcomings of these driver implementation methods are: first, the AD conversion accuracy of the hydraulic cylinder displacement signal is limited, and it is not suitable for the displacement feedback of long-stroke hydraulic cylinders. For example, the 16-bit precision AD chip must achieve 0.01mm displacement feedback accuracy. The stroke can only be limited within 600mm; second, the high precision and high speed requirements of AD conversion make it difficult to realize the driver, and at the same time, there are relatively few AD chips that meet the conversion rate of 1ms and the accuracy of more than 16 bits, and the cost is high; third, The use of a distributed structure requires technicians to have a high hardware and software foundation. For example, if the industrial computer mode is used, technicians need to be familiar with data acquisition cards and industrial computer programming application technologies. SCM system hardware and software programming application technology. To sum up, the above deficiencies greatly limit the application of electro-hydraulic servo drive technology. The patented servo controller with the application number 200710125448.6 realizes the closed-loop control of the servo system through the closed-loop control unit, the drive unit and the single-chip microcomputer setting unit. It is beneficial to popularize and use of the servo controller.

Contents of the invention

The purpose of the present invention is to provide a driver applied to the electro-hydraulic position servo system, which is an integrated driver integrating displacement feedback, PID calculation and control output, and a driver with digital display, panel control and external control functions. The electro-hydraulic servo driver is a general-purpose electro-hydraulic servo driver whose operation application is similar to that of an AC inverter.

The technical scheme that the present invention solves technical problem adopts is:

Universal electro-hydraulic position servo drive includes SSI conversion module, ARM7 core, serial port level conversion module, DA conversion amplification module, power module and operation panel.

The SSI conversion module is connected with the SSI displacement sensor, has 25-bit precision, and can realize displacement feedback with a stroke of 3m, a resolution of 1um, and 1ms sampling, and is used as a pre-processing of the input signal by the driver to convert the synchronous serial signal into An asynchronous serial signal that the driver can handle.

The ARM7 core is the core of the driver, and its main functions are the writing of user programs, the processing of input signals and the generation of output signals, and the storage of system parameters. Among them, the PID control algorithm in the program takes less than 200us to calculate.

The operation panel is a visual interactive operation interface, which is mainly composed of liquid crystal display, keyboard input and LED indicator lights. One-step operation; keyboard input is convenient for users to classify and set the operating parameters of the servo system; LED indicators prompt the system operating status in real time.

The serial port level conversion module provides an external control interface for the driver, and the computer can realize real-time data communication and precise control of the system to the servo driver through the serial port level conversion module.

The DA conversion amplification module adopts the DA module provided by ARM7 itself (10-bit DA output, 1ms analog set-up time), and the output signal is a standard 0-10v voltage signal or a 4-20ma current signal, which is used for servo valve or Proportional valves provide control electrical signals.

The input power of the power module is powered by single-phase AC, the input voltage is 220V, and the output DC voltage is 3.3V and 24V, which are used to provide power for each module of the driver.

Compared with the prior art, the present invention has the following beneficial effects: compared with the traditional analog-to-digital conversion module, the SSI module integrated in the driver improves the resolution of the input signal, the resolution can reach 25 degrees of precision, and reduces the installation cost ;The operation panel of the driver is convenient for the user to set and view the operating parameters of the driver. The operation is simple and convenient, and the display is intuitive; The combination of a programmable logic controller and a computer realizes the control of the electro-hydraulic position servo system. The invention is simpler, has a higher degree of integration, is convenient to operate, and has lower cost, which is beneficial to popularization and use on a large scale.

the

Description of drawings

Figure 1 is a layout diagram of the drive interface;

Figure 2 is the driver panel layout;

Figure 3 is a schematic diagram of the driver system;

In the figure: 1. LED indicator light; 2. Setting parameters; 3. Real-time parameters; 4. Up button; 5. Run button; 6. Down button; 7. Stop button; 8. Alarm indicator light; 9. Mode Changeover switch; 10. OK button; 11. Mode button.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, an integrated driver integrating displacement feedback, PID calculation and control output, the external interface provided by it is as follows:

The SSI conversion module is directly connected to the external displacement SSI sensor, where clock+, clock- are clock signals, data+, data- are data signals, 24VDC, GND are the power interface provided by the driver for the displacement sensor, and the SSI conversion module outputs 8-bit data at a time. Sensors with precision greater than 8 bits are transmitted in multiples.

The DA conversion and amplification module is integrated in ARM7, the precision is 10 bits, and the output signal type is a standard 2-20ma current signal or a 0-10V voltage signal. The above output signal is directly connected to the servo valve, and the hydraulic actuator can be controlled through the servo valve. Perform servo control.

The serial port level conversion module is used to convert the 3.3V voltage signal inside the ARM7 into the 3V working voltage of the module, P0.0 of the ARM7 is used for sending serial data, P0.1 is used for receiving serial data, and the output of the module Connect with a 9-pin standard serial data cable.

The input power of the power module is powered by single-phase AC, the input voltage is 220V, and the output DC voltage is 3.3V and 24V, which are used to provide power for each module of the driver.

The operation panel consists of three parts: liquid crystal display, keyboard input and LED indicator lights. The port P0.27-P1.22 of ARM7 is connected to the liquid crystal display module to provide the word control signal and bit control signal of the digital tube. The liquid crystal display module is connected to the multi-digit digital tube of the operation panel to display the operating status and real-time parameters of the driver. ; The keyboard input module is connected to the 7 buttons on the operation panel, and the ports P0.20-P0.26 of the ARM7 correspond to the control signals of the 7 buttons respectively. The LED indicator module is controlled by ports P1.23-P1.30 of ARM7, and is used to display the indicator lights on the operation panel.

As shown in Figure 2, the operation panel provides the operator with a visual interactive operation interface, which mainly consists of three parts: LCD display, keyboard input and LED indicators:

The liquid crystal display part is used to display the setting parameter 2 and real-time parameter 3 of the driver. The setting parameter 2 includes the start position, the end position, etc., and the real-time parameter 3 includes displacement, speed, acceleration, etc., and the different parameters can be selected by pressing the up button 4, Down button 6 to toggle.

The keyboard input part includes 6 buttons and a mode switch 9. The 6 buttons are: mode button 11, up button 4, run button 5, stop button 7, down button 6, and ok button 10. The mode selection button 11 is used to select different setting parameters; the up button 4 displays the previous setting parameter or sets the value of the parameter; the down button 6 displays the next setting parameter or sets the value of the parameter; the OK button 10 is used to confirm the parameters set by the user; the operation button 5 activates the user's parameter setting and drives the driver, when the operation button 5 is pressed, the driver starts to work; the stop button 7 stops the operation of the driver, and when the stop button 7 is pressed, the driver stops Work; the system mode changeover switch 9 converts the operation mode of the drive, and the drive provides the user with two types of operation modes: automatic and manual;

LED indicator light 1 prompts the operating mode and status of the system. There are two types of system operating modes: automatic and manual. The running and stop LED indicators are used to indicate the operating status of the system. The forward and reverse LED indicators indicate the movement of the hydraulic actuator. direction. The warning indicator light 8 is used to prompt the state of the system, and when the system goes wrong, the warning indicator light 8 lights up, and the driver buzzes.

As shown in Figure 3, the system principle of the driver is as follows:

First, the user uses the operation panel to set the system parameters. The user uses the mode switch (9) to select the operating mode of the drive. After setting the parameters, press the run button (5), and the drive starts to work.

Then, the driver uses a 25-bit high-precision SSI displacement sensor to collect the actual displacement signal, and outputs the signal Pv to the ARM7 core of the driver, and compares the output signal Pv with the theoretical displacement Sp output by the automatic curve generator or manual curve generator to generate an error signal Er, the pre-programmed PID calculation module in the system calculates and generates the output signal PIDout through the processing of the error signal Er, and the output signal PIDout needs to be processed by digital-analog amplification to generate a standard voltage Uout or current signal Iout, so as to control the servo valve, etc. The driving mechanism performs real-time servo control on the position of the hydraulic cylinder and other actuators.

Finally, the position signal of the actuator is collected by the SSI displacement sensor and enters the next control cycle.

Claims (1)

1. universal electro-hydraulic position servo driver comprises that SSI modular converter, ARM7 core, serial ports level switch module, DA change amplification module, power module and guidance panel, is characterized in that:

The external SSI displacement transducer of described SSI modular converter connects, and as the pre-process of driver to input signal, the synchronous serial signal is converted into the asynchronous serial signal that driver can be handled;

Described ARM7 core is the core of driver, and it is used for the processing of input signal and produces the storage of exporting signal, systematic parameter;

Described guidance panel is a Visual Interactive operation interface; Mainly form by liquid crystal display, keyboard input and LED light; Liquid crystal display is used for the running status and the real-time parameter of display driver, and the handled easily personnel grasp the running status of system and carry out next step operation; Keyboard input makes things convenient for the user that the operational factor of the servo-drive system branch parameter of classifying is specifically set; LED light real-time prompting system running state;

Described serial ports level switch module is that driver provides external control interface, and computing machine can be crossed the serial ports level switch module servo-driver is realized the real-time Communication for Power of data and the accurate control of system;

The DA module that described DA conversion amplification module adopts ARM7 self to provide, the output signal is the 0-10v voltage signal of standard or the current signal of 4-20ma, for servo-valve or proportioning valve provide the control electric signal;

Described power module input power supply is supplied power by single-phase alternating current, and input voltage is 220V, and output dc voltage 3.3V and 24V are used for power supply to each module of driver being provided.

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